The present disclosure generally relates to near-eye display (NED) systems, and specifically relates to a liquid crystal structure for controlling brightness uniformity in a waveguide display.
A NED that includes a waveguide-based display uses a two-dimensional pupil expander to achieve pupil matching between a human vision system and a waveguide-based display system of the NED. However, in a two-dimensional pupil expansion system, light propagates through a waveguide in multiple paths with an approximately same optical path length. Because of that, some light intensity signals are canceled on the waveguide, whereas some other light intensity signals are superimposed on the waveguide. Due to this multipath interference effect, the brightness of image light emitted from a waveguide-based display is non-uniform, which negatively affects visual experience.